Sydney water supply assured

Sydney water supply assured

Greater Sydney’s water supply is large and secure, holding enough water to meet demand for at least two years, even in the highly unlikely event of zero inflows.

Even under a repeat of the worst drought on record, Sydney’s storage levels would only fall to around 30% of capacity.

WaterNSW projections confirm there is already enough water in the storages to ensure supply until at least mid-2020, and in some areas late-2021, even under the continuing drought.

The improbability of that scenario is highlighted by the fact that Sydney’s average annual rainfall is more than 1200mm. Greater Sydney’s water storage dams are at 65% of capacity – nearly twice the 34% level reached during the millennium drought. WaterNSW has assessed each storage supply chain based on an annual demand of 600 gigalitres, assuming no inflows and the scaled introduction of water restrictions.

The results confirm that there is currently sufficient water already in storage to supply from the Macarthur, Nepean and Illawarra storages until at least July 2020.

In the case of the Woronora supply and the main Warragamba/Prospect system without inflows there is enough water to maintain supply until at least October 2021.

WaterNSW CEO David Harris said there is two years’ water supply in Sydney’s storages and agencies are planning for the worst, however unlikely that scenario might be.

“There is cause for the precautionary planning that is taking place by the NSW Government, WaterNSW and Sydney Water, but there is certainly no cause for concern,” Mr Harris said.

“We have a plan to secure Sydney’s water supply, and we are following that - the timing of any future triggers is going to be dependent on rainfall.

“We have about two years’ supply banked in our dams, an adaptable network with the ability for internal transfers to tackle pressure points, and a dependable, well-tested plan to guarantee supply.

“Sydney’s dams are two-thirds full, and its supply network is interconnected and adaptable.”

Sydney’s annual average rainfall is 1215mm according to records at Observatory Hill dating back to 1858. Sydney has had three years exceeding that average since 2013 (1344.4mm in 2013, 1337.2mm in 2015 and 1385.6mm in 2016).